GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The power steering control module (PSCM) receives a vehicle speed message from the engine control module (ECM) via the class 2 serial data circuit. The PSCM uses this vehicle speed message, and other inputs, to determine the desired amount of steering assist.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0000 - Vehicle Speed Information Circuit

Conditions for Running the DTC

    • The ignition is ON.
    • DTC U1300, U1301, or U2100 are not set.
    • Vehicle speed is greater than 8.1 km/h (5 mph).

Conditions for Setting the DTC

The PSCM receives an invalid, or no vehicle speed message from the ECM.

Action Taken When the DTC Sets

    • DTC C0000 is stored in memory.
    • The instrument panel cluster (IPC) message center displays the PWR STR warning message.
    • Steering assist level defaults to 120 km/h (74.5 mph) vehicle speed level of assist.

Conditions for Clearing the DTC

    • A current DTC will clear on the next malfunction free ignition cycle.
    • A history DTC will clear after 100 consecutive malfunction free ignition cycles.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests for the presence of vehicle speed related DTCs in the control modules where the vehicle speed message originates.

Step

Action

Yes

No

Schematic Reference: Power Steering Schematics

Connector End View Reference: Power Steering Connector End Views

1

Did you perform the Diagnostic System Check-Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. Select the Engine and Transmission Diagnostic Trouble Codes (DTC) function in Powertrain with a scan tool.

Does the scan tool display any engine or transmission DTCs?

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Go to Step 3

3

  1. Clear the electric power steering (EPS) DTCs with the scan tool.
  2. Operate the vehicle within the conditions for running the DTC.

Does DTC C0000 reset?

Go to Step 2

System OK